Process of making knives.



P. Z. KOHLHAAS.

PROCESS OF MAKING KNIVES. APPLIOATIION FILED 001'. 4. 1913.

1,1 14,889. Patented 0ct.27,1914.

2 SHEETS-SHEET 1.

P. Z. KOHLHAAS. PROCESS OF MAKING KNIVES.

APPLIOATION FILED OUT. 4, 1913. I 1,1 14,889. Patented Oct. 27, 1914.

2 SHEETS-$111311! 2.

wi/tnesses flue/2507" PETER ZIRLBES KOHLHAAS, OF CHICAGO, ILLINOIS.

PROCESS OF MAKING KNIVES.

Specification of Letters Patent.

Application filed October 4, 1913. Serial No. 793,302.

Patented Oct. 27, 1914.

To all whom it may concern Be it known that I, PETER Zmnns KOHL- HAAS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Processes for Making Knives, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to the art of manufacturing cutlery and its object is to provide an improved process whereby a high class knife may be manufactured at a comparatively small cost. a

The knife which by my improved process I am enabled to produce can be manufactured in large quantities for a fractional art. of the cost of producing similar knives y former processes.

My improved process will be better understood by referring to the following description, in which reference is made to the 25 accompanying drawings; in which Figure 1 is a view illustrating how the knife blanks are stamped from sheet steel; Fig. 2 is a cross-sectional view of the blade portion of one of the blanks; Fig. 3 is a view illustrating how the blade portions of the blank are sharpened in a toggle forming machine; Fig. 4 is a View of the parts shown in Fig. 3, in this instance the sharpening operation having taken place when the knife is being dropped from between the die members; Fig. 5 is a view of the blank after it has been sharpened by subjecting it to the pressure of the toggle die members; Fig. 6 is a cross-sectional view taken on the line 6, 6, in Fig. 5; Fig. 7 is a view of the blank after it has been shaped by a suitable. trimming operation, Fig. 8 is a view of the blank after the handle portion thereof has been dished in a suitable forming machine; Fig. 9 is a sectional View of the handle portion of the blank after it has been dished as shown in Fig. 8, this figure being taken on the line 9, 9 of Fig. 8; Fig. 10 is a cross-sectional view of the handle portion after it has been partially folded in the process of formingthe knife handle; Fig. 11 is a crosssectional view of the knife handle after the folding of the handle portion of the blank has been completed; Fig. 12 is a more or less diagrammatic View of the tempering tank and apparatus for conveying tempered sectional view taken on the line 14, 14 of Fig. 13; and Fig. 15 illustrates the preferredform of apparatus for sharpening the knife blanks by pressure.

In Fig. 1 of the drawings I have illustrated at 16 a sheet of machine steel from which I stamp the blanks 17 of which I form knives by my improved process. The sheet-of metal is of substantially uniform thickness throiwhout and consequently the blade portion of each of the blanks is without a cutting edge when it is stamped from the sheet metal. After I have stamped a blank from sheet metal I place the same between the toggle die-members of a novel forming machine to shar en one edge of the blade portion of the iilank. It is unnecessary to heat the blanks to soften the material of which the blanks are made, the sharpening being accomplished with the blank cold by means of the enormous pressure exerted upon the edge of the blank by the toggle die members when the same are operated.

As shown in Figs. 3 and 4, the apparatus by means of which I accomplish the shapening of the blanks consists of a pair of pivoted die members 18 having their free ends adjacent each other. The free end of one of the die members is provided with a suitable ledge 19 for supporting a knife blank prior to the operation of the toggle die members. The normal positions of thedie members are illustrated in dotted lines in Fig. 3. A blank is placed between the toggle die members and upon the ledge 19, as is clearly shown in Fig. 3. The die members are then pressed downwardly past the line through their pivotal points to the positions illustrated in Fig. 4. Owing to the fact that the adjacent ends of the tog le die members are rounded, as shown, 51o upper edge of the blank is subjected to enormous pressure and is given the crosssection illustrated in Fig. 6. Owing to the fact that it is possible to sharpen the blanks Without heating the same, it is apparent of course that blanks may be passed immediately from the punch press, after they have been stamped from the sheet metal, to

the machine provided with the toggle die members and thenw to the machine which performs the next step in the process without any loss of time. After the bladepor tion of the blank is dished as shown in Fig.

- other portion.

8, the cross-section of the handle portion after this dishing operation has takenplace being shown in Fig. 9. It will be unnecessary for me to go into the details of the appara tus for dishing the handle portion of the blank, for the reason that any expert machinist or die maker will understand how to make the male and female dies to accom plish this work.

After the handle portion of the blank has been dished, as shown in Figs. 8 and 9, it is partially folded as illustrated in Fig. 10, one portion of the handle portion being d-isposed at substantially right angles to the After the handle portion has been partially folded as shown in Fig. 10, the fold. is completed to give it the conformation shown in cross-section in Fig. 11. The handle portion has now the cross-section of an ordinary knife handle, the total thickness of the handle being considerably greater than the thickness of the sheet steel from which the blank was stamped.- The next step in the process is to convert the machine steel blank, which has now assumedthe conformation of a knife, into tool steel. After the machine steel has been converted. into tool steel, it will be too soft to retain a good.

edge. Consequently Itemper the same by heating the knife until it is cherry red and then immerse the same in the water contained in the tank 20, illustrated in Fig. 12. After the knife has been so tempered it is exceedingly hard but also very stifi and brittle and can be readily broken by bending the same or striln'ng it a shar blow.

As shown in Fig. 12, the tan 20 has associated therewith a suitable belt conveyer 21 provided with transverse bars 22 for engaging and carrying the knives which are immersed in the water in the tank 20. The conveyer 21 carries the knives out-of the tank 20 and deposits them upon another conveyer 23. The conveyer 23 carries the knives through as'uitable oven in which is maintained a temperature of substantially 500 F. After the knives have been so submitted' to this last-mentioned heating or; drawing, the knife is still very hard and capable of retaining a good edge and is also very flexible. After the knife has been drawn as set forth, the handle portion, of

the same is coated with a solution of rubber enamel, after which the knife is heated in an oven to bake the enamel. In Fig. 14 is illustrated the cross-section -of the knife handle after the-enamel has been so applied and baked. I

In Fig. 15 I have illustrated the preferred form of apparatus for sharpening the knife 1,114.,sea

blanks by pressure. This apparatus comprises a pillow block 24 'mounted upon a bolster block 25, carried by the framework of an ordinary punch press. Pivoted in the pillow block 24 are the toggle die members 26, the free ends of which face each other. lln-order to facilitate the positioning and removal of the die members, one of the die members is preferably mounted in a suit able block 25 secured to the pillow block 24. The other die member 'is pivoted to a block 27 which is normally fixed in the position shown in the drawings, but under certain circumstances is capable of reciprocating in the pillow block, as will be hereinafter pointed out. Bearingagainstthe under side of each of the die members is a compression spring 28, which normally tends to hold the die members in the positions shown in Fig. 15. The pillow block is provided with suitable screws serving as stops to determine the normal positions of the die members. before stated, the pillow block is carried by the framework of a punch press. The reciprocating head 29 of the punch press is utilized to operate the toggle die members, the said head being provided with a bracket 30 extending down past the die members and provided with an oflset portion arranged to draw the die members to normal position upon the upward movement of the reciprocating head. The head is provided with suitable rollers which positivelyengage the upper portions of the, die members after a compression spring 31 interposed between the head and the die members has been compressed. By providing the spring 31 I am enabled to secure a novel mode of operation. A blank located between the die members is first securely clamped between the die members when the spring 31 is compressed, and is thus held in proper position. After therollers of the reciprocating head come. into positive engagement with the die mem-' bers, the die members are of course forced downwardly past the line through their pivotal points, and the knife blank is accordingly sharpened, as above set forth.

As shown, the block 27 may be provided with a plurality of tenons 31 for engaging in corresponding slots in the pillow block.

It will then be seen that operation of .the-

toggle die members will serve to reciprocate the block 27 within the pillow block and so bring the dies carried by the blocks 27 lllld and 32 into engagement with each other. The blocks 27 and 32 may, if desired, be

provided with dies for accomplishing the dishing of the handle portion of the knife blank.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The process of making a knife which consists in stamping from sheet metal an integral blank comprising a blade portion and a handle portion of greater width, sharpening one edge of the blade portion by pressure and folding the handle portion to produce a knife handle of greater thickness than the thickness of the sheet from which tion and a body portion, and sharpening one edge of the blade portion by pressure.

3. The process of making a knife which consists in stamping a blank from sheet metal, sharpening one edge of the blank by pressure alone, and tempering the blank.

4:. Theprocess of making a knife which consists in stamping a blank from sheet metal of substantially uniform thickness, and then sharpening one edge of the blank by pressing it gradually and increasingly from side to side.

5. The process of making a knife which consists in stamping a blank from a sheet of metal of substantially uniform thickness, sharpening an edge of the blank by pressing it gradually and increasingly from side to side and then tempering the sharpened blank.

In witness whereof, I hereunto subscribe my name this 18th day of September, A. D. 1913.

PETER ZIRBES KOHLHAAS.

Witnesses LESLIE W'. FRIcKn, LEONARD E. Boone. 

